The photoreceptor function of retinal rod cell shall be examined by means of the structure and dynamic properties of rod outer segment disk membranes. These membranes are isolated from rod outer segments (ROS), swollen into spherical vesicles in hypotonic media and suspended into a homogeneous dilution solution. The experimental techniques are elastic, quasielastic and electrophoretic light scatterings, forward depolarized scattering and electric field-induced birefringence transient (dynamic Kerr effect). The variables of suspending medium for membrane vesicles are chosen to test the calcium transmitter model of Hagins and Yoshikami. Focus will be placed on the photo-induced changes in the calcium binding isotherms and their temperature effect. Since the electrophoretic light scattering technique is able to distinguish between vesicle surface-bound calcium and influxed one, the variables which affect the binding constant and binding site number will receive most attention relative to the calcium transmitter model.